/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.catalina.mbeans;

import java.io.IOException;
import java.io.Serializable;
import java.lang.management.ManagementFactory;
import java.net.MalformedURLException;
import java.net.Socket;
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.server.RMIClientSocketFactory;
import java.rmi.server.RMIServerSocketFactory;
import java.util.HashMap;

import javax.management.MBeanServer;
import javax.management.remote.JMXConnectorServer;
import javax.management.remote.JMXConnectorServerFactory;
import javax.management.remote.JMXServiceURL;
import javax.management.remote.rmi.RMIConnectorServer;
import javax.rmi.ssl.SslRMIClientSocketFactory;
import javax.rmi.ssl.SslRMIServerSocketFactory;

import org.apache.catalina.Lifecycle;
import org.apache.catalina.LifecycleEvent;
import org.apache.catalina.LifecycleListener;
import org.apache.tomcat.util.res.StringManager;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;

/**
 * This listener fixes the port used by JMX/RMI Server making things much
 * simpler if you need to connect jconsole or similar to a remote Tomcat
 * instance that is running behind a firewall. Only the ports are configured via
 * the listener. The remainder of the configuration is via the standard system
 * properties for configuring JMX.
 */
public class JmxRemoteLifecycleListener implements LifecycleListener {

	private static Log log = LogFactory
			.getLog(JmxRemoteLifecycleListener.class);

	/**
	 * The string resources for this package.
	 */
	protected static final StringManager sm = StringManager
			.getManager(Constants.Package);

	protected int rmiRegistryPortPlatform = -1;
	protected int rmiServerPortPlatform = -1;
	protected boolean rmiSSL = true;
	protected String ciphers[] = null;
	protected String protocols[] = null;
	protected boolean clientAuth = true;
	protected boolean authenticate = true;
	protected String passwordFile = null;
	protected String loginModuleName = null;
	protected String accessFile = null;
	protected boolean useLocalPorts = false;

	protected JMXConnectorServer csPlatform = null;

	/**
	 * Get the port on which the Platform RMI server is exported. This is the
	 * port that is normally chosen by the RMI stack.
	 * 
	 * @returns The port number
	 */
	public int getRmiServerPortPlatform() {
		return rmiServerPortPlatform;
	}

	/**
	 * Set the port on which the Platform RMI server is exported. This is the
	 * port that is normally chosen by the RMI stack.
	 * 
	 * @param theRmiServerPortPlatform
	 *            The port number
	 */
	public void setRmiServerPortPlatform(int theRmiServerPortPlatform) {
		rmiServerPortPlatform = theRmiServerPortPlatform;
	}

	/**
	 * Get the port on which the Platform RMI registry is exported.
	 * 
	 * @returns The port number
	 */
	public int getRmiRegistryPortPlatform() {
		return rmiRegistryPortPlatform;
	}

	/**
	 * Set the port on which the Platform RMI registry is exported.
	 * 
	 * @param theRmiRegistryPortPlatform
	 *            The port number
	 */
	public void setRmiRegistryPortPlatform(int theRmiRegistryPortPlatform) {
		rmiRegistryPortPlatform = theRmiRegistryPortPlatform;
	}

	/**
	 * Get the flag that indicates that local ports should be used for all
	 * connections. If using SSH tunnels, or similar, this should be set to true
	 * to ensure the RMI client uses the tunnel.
	 * 
	 * @returns <code>true</code> if local ports should be used
	 */
	public boolean getUseLocalPorts() {
		return useLocalPorts;
	}

	/**
	 * Set the flag that indicates that local ports should be used for all
	 * connections. If using SSH tunnels, or similar, this should be set to true
	 * to ensure the RMI client uses the tunnel.
	 * 
	 * @param useLocalPorts
	 *            Set to <code>true</code> if local ports should be used
	 */
	public void setUseLocalPorts(boolean useLocalPorts) {
		this.useLocalPorts = useLocalPorts;
	}

	private void init() {
		// Get all the other parameters required from the standard system
		// properties. Only need to get the parameters that affect the creation
		// of the server port.
		String rmiSSLValue = System.getProperty(
				"com.sun.management.jmxremote.ssl", "true");
		rmiSSL = Boolean.parseBoolean(rmiSSLValue);

		String protocolsValue = System
				.getProperty("com.sun.management.jmxremote.ssl.enabled.protocols");
		if (protocolsValue != null) {
			protocols = protocolsValue.split(",");
		}

		String ciphersValue = System
				.getProperty("com.sun.management.jmxremote.ssl.enabled.cipher.suites");
		if (ciphersValue != null) {
			ciphers = ciphersValue.split(",");
		}

		String clientAuthValue = System.getProperty(
				"com.sun.management.jmxremote.ssl.need.client.auth", "true");
		clientAuth = Boolean.parseBoolean(clientAuthValue);

		String authenticateValue = System.getProperty(
				"com.sun.management.jmxremote.authenticate", "true");
		authenticate = Boolean.parseBoolean(authenticateValue);

		passwordFile = System.getProperty(
				"com.sun.management.jmxremote.password.file",
				"jmxremote.password");

		accessFile = System.getProperty(
				"com.sun.management.jmxremote.access.file", "jmxremote.access");

		loginModuleName = System
				.getProperty("com.sun.management.jmxremote.login.config");
	}

	public void lifecycleEvent(LifecycleEvent event) {
		// When the server starts, configure JMX/RMI
		if (Lifecycle.START_EVENT == event.getType()) {
			// Configure using standard jmx system properties
			init();

			// Prevent an attacker guessing the RMI object ID
			System.setProperty("java.rmi.server.randomIDs", "true");

			// Create the environment
			HashMap<String, Object> env = new HashMap<String, Object>();

			RMIClientSocketFactory csf = null;
			RMIServerSocketFactory ssf = null;

			// Configure SSL for RMI connection if required
			if (rmiSSL) {
				csf = new SslRMIClientSocketFactory();
				ssf = new SslRMIServerSocketFactory(ciphers, protocols,
						clientAuth);
			}

			// Force the use of local ports if required
			if (useLocalPorts) {
				csf = new RmiClientLocalhostSocketFactory(csf);
			}

			// Populate the env properties used to create the server
			if (csf != null) {
				env.put(RMIConnectorServer.RMI_CLIENT_SOCKET_FACTORY_ATTRIBUTE,
						csf);
			}
			if (ssf != null) {
				env.put(RMIConnectorServer.RMI_SERVER_SOCKET_FACTORY_ATTRIBUTE,
						ssf);
			}

			// Configure authentication
			if (authenticate) {
				env.put("jmx.remote.x.password.file", passwordFile);
				env.put("jmx.remote.x.access.file", accessFile);
				env.put("jmx.remote.x.login.config", loginModuleName);
			}

			// Create the Platform server
			csPlatform = createServer("Platform", rmiRegistryPortPlatform,
					rmiServerPortPlatform, env, ManagementFactory
							.getPlatformMBeanServer());

		} else if (Lifecycle.STOP_EVENT == event.getType()) {
			destroyServer("Platform", csPlatform);
		}
	}

	private JMXConnectorServer createServer(String serverName,
			int theRmiRegistryPort, int theRmiServerPort,
			HashMap<String, Object> theEnv, MBeanServer theMBeanServer) {

		// Create the RMI registry
		try {
			LocateRegistry.createRegistry(theRmiRegistryPort);
		} catch (RemoteException e) {
			log.error(sm.getString(
					"jmxRemoteLifecycleListener.createRegistryFailed",
					serverName, Integer.toString(theRmiRegistryPort)), e);
			return null;
		}

		// Build the connection string with fixed ports
		StringBuffer url = new StringBuffer();
		url.append("service:jmx:rmi://localhost:");
		url.append(theRmiServerPort);
		url.append("/jndi/rmi://localhost:");
		url.append(theRmiRegistryPort);
		url.append("/jmxrmi");
		JMXServiceURL serviceUrl;
		try {
			serviceUrl = new JMXServiceURL(url.toString());
		} catch (MalformedURLException e) {
			log.error(sm.getString("jmxRemoteLifecycleListener.invalidURL",
					serverName, url.toString()), e);
			return null;
		}

		// Start the JMX server with the connection string
		JMXConnectorServer cs = null;
		try {
			cs = JMXConnectorServerFactory.newJMXConnectorServer(serviceUrl,
					theEnv, theMBeanServer);
			cs.start();
			log.info(sm.getString("jmxRemoteLifecycleListener.start", Integer
					.toString(theRmiRegistryPort), Integer
					.toString(theRmiServerPort), serverName));
		} catch (IOException e) {
			log.error(sm
					.getString("jmxRemoteLifecycleListener.createServerFailed",
							serverName), e);
		}
		return cs;
	}

	private void destroyServer(String serverName,
			JMXConnectorServer theConnectorServer) {
		if (theConnectorServer != null) {
			try {
				theConnectorServer.stop();
			} catch (IOException e) {
				log.error(sm.getString(
						"jmxRemoteLifecycleListener.destroyServerFailed",
						serverName), e);
			}
		}
	}

	public static class RmiClientLocalhostSocketFactory implements
			RMIClientSocketFactory, Serializable {
		private static final String FORCED_HOST = "localhost";

		private RMIClientSocketFactory factory = null;

		public RmiClientLocalhostSocketFactory(RMIClientSocketFactory theFactory) {
			factory = theFactory;
		}

		public Socket createSocket(String host, int port) throws IOException {
			if (factory == null) {
				return new Socket(FORCED_HOST, port);
			} else {
				return factory.createSocket(FORCED_HOST, port);
			}
		}

	}
}
